Accessing folder on OS/X fails

When I attempt to visit folders in the Keybase client, I get an error page “Ghhh. Try this.”

The instructions – “Open your macOS Security & Privacy Settings and follow these steps” – fail me. The picture implies I should see “System software developer “Keybase, Inc.” was blocked from loading.” but that does not appear in the dialogue box.

How can I enable this setting, when the Security & Privacy Settings dialogue is apparently unaware of Keybase?

I'm using Keybase version 1.0.45-20180305194145+3a1c65a05, on macOS 10.13.3.

Reproduce the folder-access failure using Keybase version 1.0.45 on macOS 10.13.3, then review the Security & Privacy Settings instructions and the corresponding dialogue. Done means the client can open folders and the instructions identify a setting that is actually available on that macOS version.

Written by the indexing model from the issue text.